D.9 Apply single-case experimental designs

Applying single-case experimental designs involves using research methods that focus on one individual or a small group to evaluate the effectiveness of an intervention. In these designs, the behavior of interest is measured repeatedly over time, both before and after the intervention, to determine whether the changes in behavior are due to the intervention.

Example: A BCBA is working with a child who exhibits frequent aggressive behaviors in the classroom. The BCBA applies a reversal design (ABAB design) to evaluate the effectiveness of a token economy system as an intervention. In the baseline (A) phase, the child’s aggressive behavior is recorded without intervention. The token economy is introduced in the intervention (B) phase, and the child earns tokens for appropriate behavior. After seeing a decrease in aggression, the BCBA removes the intervention (A) to observe whether the behavior returns to baseline levels and then reintroduces the token economy (B) to confirm its effectiveness.